Post on 25-Dec-2015
transcript
Genetic Engineering
“Amazing Schemes Within Your Genes”
What is genetic engineering?
Moving small pieces of DNA from one organism into another organism
What is recombinant DNA technology? Same thing as genetic engineering Recombinant DNA – made by
connecting (splicing) fragments of DNA from different sources
How does recombinant DNA work? DNA is inserted into
an organism Organism uses
foreign DNA as if it were its own
What are these new things called? Transgenic organisms
– contain recombinant DNA (initial + “foreign”)
How do scientists move DNA (genes) to make transgenic organisms?1. Isolate source of foreign DNA to be
inserted
2. Join DNA with a vehicle that can transport it
3. Transfer DNA (from chromosomes) into new host
How is DNA isolated?
Restriction enzymes are used
What are restriction enzymes?
Proteins that come from bacteria
They recognize, bind to and cut DNA into smaller fragments at certain points
>200 different enzymes
Examples are: EcoRI, HinD III, Bam HI, Bgl II
Isolate source of DNA
Ex: EcoRI – cuts between G and A whenever it sees CTTAAG
A G G T C T T A A G C T A G C
T C C A G A A T T C G A T C G
Isolate source of DNA
Don’t cut straight through both DNA strands
Cut is offset by a few bases “Sticky” ends are produced
C T T A A G
G A A T T C
C T T A A G
G A A T T C
Isolate source of DNA
Ex: AluI – cuts between C and G whenever it sees AGCT
A G C TT C G A
A G C TT C G A
“Blunt” ends are produced
Isolate source of DNA
Sticky Ends DNA can form circle because
complementary bases
OR
DNA can pair with any other DNA fragment cut by the same enzyme (same bases exposed) = Recombinant DNA
REFRESHER: How do scientists move DNA (genes)?1. Isolate source of DNA
Answer: through Restriction Enzymes
2. Join DNA to a vehicle that can transport itAnswer: ???
3. Transfer DNA (from chromosomes) into target cell
Answer: ???
Join DNA to a transport vehicle
Vector
– means by which DNA from one organism gets to target/host cell
Types of Vectors
1. Mechanical Micropipette inserted into cell Gene gun shoots tiny metal bullet coated w/
DNA
2. Biological Virus Plasmid
What is a plasmid?
A small ring of DNA found in bacteria, which only carries genes under extreme circumstances
Both plasmid and foreign DNA are cleaved w/ same restriction enzyme
They are spliced using a “glue” called a ligase (enzyme)
How do we know if foreign DNA has been successfully transferred?
Host cell copies recombinant DNA and its own DNA
Clones are created as host continues to divide (all w/ desired DNA)
Foreign DNA codes for the production of a specific protein – test the cloned cells to see if they produce protein or not
And the final product is…
Newly recombined DNA that undergoes mitosis, producing multiple copies of new DNA
Bacteria is considered a good host because it reproduces quickly
Genetically Engineered